(color online) (a) The electric field of a spatially inhomogeneous laser pulse (800 nm, 1.0 × 10 15 W / cm 2 ) at x = 0 from 0.5 o.c. to 3.5 o.c., the gray dot represents the electron. (b) Dependence of the kinetic energy on the recombination time (green circles for the first rescattering and red circles for the second rescattering) for β = 0.0065. (c) Electron trajectories for the electrons obtaining maximum energy in the first rescattering (blue line) and the second rescattering (red line) processes. (d) The enlargement of panel (c) in the time period from 1.22 o.c. to 1.32 o.c.